
Erasing a disk or volume
You use Disk Utility to erase disks and volumes.
Erasing a disk deletes all the volumes and files on the disk. Erasing a volume deletes all the files on that volume, but does not affect other volumes. Erasing a recordable disc, such as a CD-RW or DVD-RW disc, creates a blank disc with no formatting.
IMPORTANT: If you have any files you want to save, be sure to copy them to another disk before you erase the disk they are on.
Usually when you erase a disk or volume, Disk Utility erases only the information used to access the files on the disk, not the actual files. Because of this, the erased files can be recovered. If you want to erase a disk so that the files cannot be recovered, you can select security options to write zeros over the disk space.
- If you want to erase an external disk, connect the disk to your computer.
- In Disk Utility, select the disk or volume in the list on the left.
- Click Erase.
- Choose a format from the Volume Format pop-up menu. Usually you will choose Mac OS Extended (Journaled).
- Type a name for the disk or volume.
- If you're erasing a disk and plan to use the disk with Mac OS 9, select the checkbox to install the Mac OS 9 drivers.
You do not need to install the Mac OS 9 drivers to use the disk with the Classic environment.
- If you want to erase the entire contents of the disk by writing zeros, click Security Options, then select the option you want and click OK.
- Click Erase.
To erase your computer's startup disk, you must start up from another disk. You can use your Install Mac OS X disc.